3GPP Rel-19 Toward 6G
SungDuck Chun
1. Abstract
The 5G system achieves a breakthrough increase in the key performance indicator of communication systems, compared to the previous generation 4G system. In addition, the 5G
system introduced new functionalities supporting various emerging application scenarios.
Based on the success of the 5G system, the 6G system is likely to emerge around end of
2020s. There are many ongoing activities to define requirements of the 6G system. Recently,
3GPP SA1 started various studies for Rel-19 5G systems. The outcome of the Rel-19 may not
only show the additional capability that the 5G system will bring, but also provide a guidance on what future the 6G system needs to be capable of. In this whitepaper, the ongoing
areas of the Rel-19 studies are discussed.
2. Introduction
3GPP has established itself as the premier global standard for telecommunication, from GSM (2G), WCDMA
(3G), LTE (4G) to recent NR (5G). Essentially, almost all
handsets and devices connecting to cellular networks
support at least one of these standards. On top of the
phenomenal success of the 4G system, which is commonly known as LTE, the 5G system has dramatically
increased the capability of cellular communication
system. The KPI requirements of the 5G system for
various scenario are summarized in [1].
Since the first commercial launch of the 5G system in
2018, 3GPP has continually added new features into
subsequent 3GPP releases. As illustrated in Figure 1,
Rel-15, Rel-16 and Rel-17 are the first three releases
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supporting the 5G system and provide basic features
that distinguish the 5G system from the 4G system.
The upcoming Rel-18, Rel-19 and Rel-20 are expected
to add advanced features into the 5G system and are
called as 5G-Advanced.
While 3GPP Stage-2 and Stage-3 WGs are developing
system architectures and protocols for Rel-18, 3GPP
Stage-1 WGs are discussing Rel-19 5G system-level
requirements. In the past, studies, works, and features
of Rel-13 and Rel-14 4G system became the foundation of Rel-15 5G system. Likewise, activities out of
Rel-19 of 5G system may provide a glimpse of what
future 6G system look like.
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Figure 1: 3GPP Timeline
3. Overall Rel-19 Stage-1 Status
At SA1#97 (Feb, 2022) and SA1#98 (May, 2022) meetings, 3GPP WG SA1 agreed on SIDs (Study Item
Description) for Rel-19, as shown in Table 1.
As titles of the studies suggest, 3GPP standards are
addressing more specific requirements of industries
that are considering use of 3GPP-based communication systems. In the past releases, 3GPP standards
added support for various industries. For example, to
support machine-to-machine communications, 3GPP
introduced features such as support for low energy
IoT communications, wide-coverage IoT communication, vehicle-to-vehicle communication, and so on.
However, the support in the previous releases is not
enough for some other industries, and new studies
are trying to address the needs of the other industries. For example, the study on metaverse services
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(FS_Metaverse) will address requirements arising
when 3GPP-based systems carry traffic for the application implementing metaverse scenario. On the
other hand, as new scenarios emerge when industries
adopt to use 3GPP-based communication technologies, additional studies will be required in 3GPP. For
example, studies on satellite access (FS_5GSAT_ph3)
are trying to address additional requirements from
the satellite industries, on top of previous works on
this area.
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Table 1: Rel-19 SAI Agreed SIDs
SID Acronym
Reference Tdoc
Title
FS_Sensing
SP-220084
Study on Integrated Sensing and Communication
FS_AmbientIoT
SP-220085
Study on Ambient power-enabled Internet of Things
FS_Metaverse
SP-220353
Study on Localized Mobile Metaverse Services
FS_NetShare
SP-220087
Study on Network Sharing Aspects
FS_AIML_Ph2
SP-220083
Study on AI/ML Model Transfer_Phase2
FS_RAILSS
SP-190838
Study on Supporting of Railway Smart Station Services
FS_5GSAT_Ph3
SP-220443
Study on satellite access - Phase 3
FS_UAV_Ph3
SP-220444
Study on UAV - Phase 3
FS_RVAS
SP-220442
Study on roaming value added services
FS_DualSteer
SP-220445
Study on Upper layer traffic steering, switching and split over
dual 3GPP access
FS_EnergyServ
SP-220446
Study on Energy Efficiency as service criteria
FS_SOBOT
SP-220447
Study on Network of Service Robots with Ambient
Intelligence
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3.1. Integrated Sensing and Communication
Integrated Sensing and Communication studies
scenarios where sensing functionalities are provided
by 3GPP communication system. Basically, for the
wireless communication between a transmitter and a
receiver, a lot of information of radio environment is
exchanged for the fine-tuning operation parameter
of the communication. In this process, the transmitter
and the receiver may acquire a lot of information of
radio environment, and this information may help
applications adapt its behaviour. In fact, a lot of devices/applications use sensors for the perception of
environments and for determination of action. If the
functions that the sensors provide can be cost-effectively provided by the communication system, more
compact and power-efficient operation of devices are
possible. Example scenarios are [2][3]:
Real-time monitoring of environment: Wireless
signals can be used to detect changes and conditions
of environments may enable environment related
applications to use that. For example, as the wireless
signal passes through different environment, it may
experience different changes. The quality of the
received wireless signal displays different attenuation characteristics with changes in air humidity, air
particulate matter (PM) concentration, carrier
frequency, etc. This can be used for weather or air
quality detection.
power, communication capabilities, batteries. Especially, in 3GPP’s point of view, the major focus is to
reduce power consumption for communications,
because a majority of IoT devices are cell-battery
operated. For example, optimizing message exchanges between a device and a network or reducing the
time when a device transmits/receives data may help
the device to reduce battery consumption. However,
this optimization may still be used under the assumption that the total usable amount of battery of the
device is still limited.
The Rel-19 study takes a different approach. In Rel-19
study, 3GPP are discussing whether the so-called
‘energy-harvesting’ can help communication, whether the energy-harvesting and communication can be
designed together, or how the characteristic of the
energy-harvest-based IoT device can be used for optimizing communication system. [4]
Autonomous navigation of vehicles/UAV: For the
autonomous driving of vehicles, it is essential for the
vehicles to identify humans and objects around. By
using the wireless signal generated from the smartphones of human users, the vehicles can determine
the existence of human users and potential locations
of the human users. Based on that, the vehicles can
perform driving manoeuvre to safely navigate
around humans and objects.
3.2. Ambient Power-Enabled IoT
Internet-of-Things (IoT) is a concept that has been in
the use for many years. It is about billions of sensors
or devices connected to internet, to support various
use cases, e.g., gathering sensor information remotely, controlling remotely actuators, etc. Motivations of
dedicated works for IoT devices in previous releases
were that IoT devices were limited in processing
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Example scenerio:
3GPP-based TAG: At a warehouse, a tag (e.g., information of goods, logistics, tracking) is attached to each
good. This tag is discovered, scanned and tracked by
3GPP based networks, while the tag moves. Because
this tag is 3GPP standards compliant, it may be a
cost-effective way to track goods in wide area (e.g.,
outside of warehouse, outside of factory, or on the
road) without using battery.
3.3. Localized Mobile Metaverse Services
Use of the Metaverse tools in diverse sectors evokes
several new experiences, products and services,
based on Augmented Reality (AR) and Virtual Reality
(VR) frameworks. As services based on Metaverse
concepts received a lot of attention, 3GPP SA1 decided to perform a study on this topic to derive requirements of 3GPP system. From 3GPP’s point of view, the
Metaverse refers to a persistent, shared, perceived set
of interactive perceived space, both locally and
remotely. [5][6]
The SA1 study investigates specific use cases associated with a user presenting himself or herself remotely
by means of a representation: an avatar. These use
cases provide users with immersive and interactive
media representing the remote location in which the
avatar is present. The focus of 3GPP is on the local
representation of a remote user, and interaction with
him or her. Though there were previous works on
Extended Reality (XR) media in 3GPP and support for
enhanced Mobile Broadband services, more improveOfinno ofinno.com September 2022
-ment is required. For example, for shared interactive
services in an environment in which activity is rapid,
it may be challenging to provide timely, synchronized and highly available delivery of low latency
media to enable interaction which in the area of
games perform comparable to existing sports in
terms of responsiveness.
The following are study areas:
Performance (KPI) aspects; e.g. latency, throughput,
connection density.
Efficiency and scalability aspects, for large numbers
of users in a single location.
Identification of users and other digital representations of entities interacting within the metaverse
service.
Acquisition, use and exposure of local (physical and
digital) information to enable metaverse servicesAcquiring local spatial/environmental information
and user/UE(s) information.
Exposing local acquired spatial, environmental and
user/UE information to 3rd parties to enable
metaverse services.
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3.4. AI/ML Model Transfer
In Rel-18, 3GPP already did some initial study on AI/ML, developing use cases where AI/ML applications can
utilize information of 3GPP system to optimize its operation. For example, in Rel-18, use cases where a number
of UEs are involved in Federated Learning are discussed and information exposure from 5G system to third
parties are discussed.
In Rel-19, for better support of AI/ML applications, new use cases will be studied. For example, for fast adaptation and for distributed learning application, data and models for AI/ML may be shared directly between
devices, without traversing 5G networks. This may entail further study on the privacy protection, energy
savings, etc. Also, in case of distributed learning, 5G systems need to efficiently handle scenarios such as
device’s movement into and out of coverage area, limited power, offloading computation between devices,
trade-off among AI/ML model accuracy, model generation latency, power constraint, computing capabilities,
etc.[7]
As such, the objective states studies on potential service and performance requirements to support efficient
AI/ML operations using direct device connection.
3.5. Upper Layer Traffic Steering, Switching & Split Over Dual 3GPP Access
In 5G systems, core networks are designed to support not only 3GPP-based access technologies (E-UTRA, NR),
but also non-3GPP-based access technologies such as Wi-Fi and Fixed Broadband. By designing core network
access technology agnostic, 5G systems support integration with or migration from other access technologies.
The use of non-3GPP based access technologies can be used to provide additional coverage for a wireless
device. For example, when users move from outdoors into indoors where 3GPP radio signal cannot penetrate,
the use of Wi-Fi to access 5G core networks allows the users to enjoy a continuous use of 3GPP system, without
experiencing interruption to the communication service.
The non-3GPP-based access technology can also provide additional capacity to the device. For example, when
the devices are in area where both non-3GPP based access technology and 3GPP based access technology are
available, the simultaneous use of both access technologies provides the devices increased data
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rates, additional reduction of packet delivery error. By
flexible adjustment and configuration, 3GPP system
can steer some specific traffic to use one of the available access technologies, can switch the specific
traffic from one access technology to other access
technology, and split some portion of the traffic over
one access and remaining portion of the traffic over
other access.
In Rel-19, the functionality of traffic steering, switching and split is expected to expand. From Rel-16,
3GPP incorporated support for NTN (non-terrestrial
network) and support for NPN (non-public network).
Both NTN and NPN are based on 3GPP access technologies, provides additional opportunities for connectivity. Accordingly, the ground for simultaneous use
of multiple 3GPP based access technologies are ripe.
(Fig. 2)
In this study, following combination are pursued:[8]
Single PLMN, PLMN plus (standalone) NPN, two
PLMNs
Same or different 3GPP RATs (NR or NTN, plus one of
NR, NTN or LTE)
3.6. Study on Energy Efficiency as Service
Criteria
Energy cost is taking up a big share of OPEX for a
cellular communication system. Operators puts a lot
of effort to reduce amount of energy required to run
the communication networks. In fact, there has been
much effort to reduce battery consumption of wireless devices, because the wireless device is supposed
to work on a battery for the most of time, while
network devices are plugged into a constant energy
source such as power outlet.
To reduce power consumption of network equipment
may bring some side-effect. For example, reduced
transmit power may resulted in reduced cell coverage, leading to more call drops. Or, switching off
some network equipment may result in overload in
other network equipment, or impact on quality of
service of ongoing users. For example, for the service
over URLLC network slice, the degrade in network
performance is not something that can be deprioritized for power efficiency.
As such, energy saving for a network can be taken as
one dimension while meeting QoS demand can be
taken as another dimension. The operation setting for
communication service needs to satisfy both user
experience and the energy efficiency.
Figure 2: Multiple Paths for Data Communication
Path 1: NonTerrestrial Access
Path 2: Terrestrial Access (Network 1)
Path 3: Terrestrial Access (Network 2)
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In this study[9], the objectives are:
Define and support energy efficiency criteria as part
of communication service to user and application
services.
Support information exposure on systematic energy
consumption or level of energy efficiency to vertical
customers.
4. Conclusions
In this whitepaper, we reviewed the recent 3GPP
studies ongoing for Rel-19. The Rel-19 studies is
expected to accelerate the integration of various
industries with 3GPP technologies, allowing ubiquitous connectivity. This will provide a basic ground for
future 6G system will be based on.
3.7. Study on Satellite Access - Phase 3
In previous releases, 3GPP has put a lot of effort to
support 3GPP-based communication via satellite link.
Satellite-based communication is an effective tool in
providing access to a device in areas where conventional terrestrial based communication cannot reach.
The support for satellite-based 3GPP communication
assumed that the backhaul network from the radio
access node to the core network is available, and that
the wireless device is capable of using existing GNSS
functionality.
For Rel-19 discussion, 3GPP will investigate scenarios
where the backhaul connection is intermittent. For
example, a satellite may orbit around the globe regularly, and may receive a data from a location where
direct backhaul is not available. In this scenario, the
satellite communication is required to provide
hold-and-forward capability. In other setting, a device
may use 3GPP-based satellite communication architecture, to determine its locations.[10]
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5. References
1. 3GPP Technical Specification, TS 22.261, “Service requirements for the 5G system”
2. 3GPP Technical Report, TR 22.837, “Study on Integrated Sensing and Communication”
3. 3GPP Technical document, SP-220084
4. 3GPP Technical document, SP-220085
5. 3GPP Technical Report, TR 22.856, “Study on Localized Mobile Metaverse Services”
6. 3GPP Technical document, SP-220353
7. 3GPP Technical Report, 22.876, “Study on AI/ML Model Transfer Phase2”
8. 3GPP Technical Report, 22.862, “Study on Energy Efficiency as service criteria”
9. 3GPP Technical Report, 22.841, “Study on Upper layer tra_c steering, switching and split over dual 3GPP
access”
10. 3GPP Technical Report, TR 22.865, “Study on satellite access - Phase 3”
About the Author
SungDuck Chun
Senior Technical Staff - 5G Core
SungDuck has participated in 3GPP standardization since
2003, for various working groups SA1, RAN2, SA2, SA3. He contributed to radio architecture/protocol design for HSxPA/LTE
and system/service requirements definition for 5G. He served
as rapporteur for various 3GPP work items, eV2X, MINT, EASNS
and V2XIMP. He also participated in standardization for ETSI,
5GAA, and received best contributor award from 5GAA in 2018.
Prior to joining Ofinno, he held a chief research engineer position for standardization, and a manager position for business
development at LG Electronics.
He is an inventor in over 750 granted US patents. SungDuck
focuses on research of system architecture and communication protocols for 5G and 6G. He received his MBA degree from
Sloan school of Massachusetts Institute of Technology, MA,
USA. He received his BS degree in Electrical engineering from
Seoul National University, Seoul, Korea.
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